LOS ANGELES – A Los Angeles teacher accused of taking sexually explicit photographs of his young students pleaded not guilty to 23 counts of lewd conduct at his arraignment Tuesday.

Mark Berndt, 61, allegedly took hundreds of photographs as he blindfolded young children and spoon-fed his semen to them in his classroom at Miramonte Elementary School.

The alleged offenses, which also include putting cockroaches on the children's faces, took place between 2008 and 2010 and involved students ranging in age from six to 10, police said.

Berndt is currently being held on $23 million bail. He is scheduled to appear in court again on March 28 in Los Angeles for a hearing to determine if prosecutors have enough evidence for him to stand trial, KTLA-TV reported.

He was arrested Jan. 30 after a yearlong investigation that began when a film processor discovered more than 40 photographs depicting children inside a school classroom with their eyes blindfolded and their mouths taped shut.

Following his arrest, more photos of children in bondage-like situations, allegedly taken by Berndt, were discovered by investigators on a computer at the same pharmacy where the photos that initially implicated him were found.

Investigators have found about 600 such photos, according to KTLA.

At least 24 students who claim to have been victimized by Berndt have hired attorneys for civil suits against him. Investigators said there may be about 25 more victims who have not yet been identified.